diff --git a/product/ERP5/Document/BusinessTemplate.py b/product/ERP5/Document/BusinessTemplate.py
index 2f39e314c1892132511807440c917d8ef64702d8..0987fd4deecf4a111bc3c4976fdf667bc1bd6845 100644
--- a/product/ERP5/Document/BusinessTemplate.py
+++ b/product/ERP5/Document/BusinessTemplate.py
@@ -5553,6 +5553,8 @@ Business Template is a set of definitions, such as skins, portal types and categ
                   'install_object_list_list', 'id_generator', 'bt_for_diff'):
           continue
         value = self.getProperty(id)
+        if value is None:
+          continue
         if prop_type in ('text', 'string', 'int', 'boolean'):
           bta.addObject(obj=value, name=id, path=path+os.sep+'bt', ext='')
         elif prop_type in ('lines', 'tokens'):
diff --git a/product/ERP5/Tool/TemplateTool.py b/product/ERP5/Tool/TemplateTool.py
index bc9b203a9e11b94384b7f02a9ce4b63eb5b66608..c8591b8fff42955bd341e17c8b040c5e90d09999 100644
--- a/product/ERP5/Tool/TemplateTool.py
+++ b/product/ERP5/Tool/TemplateTool.py
@@ -256,6 +256,11 @@ class TemplateTool (BaseTool):
             except KeyError:
               continue
             value = tar.extractfile(info).read()
+            if value is 'None':
+              # At export time, we used to export non-existent properties:
+              #   str(obj.getProperty('non-existing')) == 'None'
+              # Discard them
+              continue
             if prop_type == 'text' or prop_type == 'string' \
                                    or prop_type == 'int':
               prop_dict[pid] = value
@@ -320,6 +325,11 @@ class TemplateTool (BaseTool):
           if not os.path.exists(prop_path):
             continue          
           value = open(prop_path, 'rb').read()
+          if value is 'None':
+            # At export time, we used to export non-existent properties:
+            #   str(obj.getProperty('non-existing')) == 'None'
+            # Discard them
+            continue
           if prop_type in ('text', 'string', 'int', 'boolean'):
             prop_dict[pid] = value
           elif prop_type in ('lines', 'tokens'):